A "positive reaction" means responding in a good or favorable way. It usually refers to when someone reacts with approval, excitement, or happiness towards something. Full definition
It helped him get more positive reactions from customers and ultimately close more sales. (inc.com)
You're actually much more likely to get positive reactions from her. (datingadvice.com)
Much to my surprise, I received thousands of positive reactions from readers who share my love of homemade, local, and beautiful «slow fashion» items. (treehugger.com)